Circuit breaker



Feb. 25, 1936.

CIRCUIT BREAKER Filed March 2, 1954 ,3 Q, [Aira/MuvoJ INVENTOR Haro/a E'. ELL/5b ATTORNEYS H. E. COBB Y 2,032,115

Patented Feb. 25, 1936 PATENT OFFICE CIRCUIT BREAKER .Harold E. Cobb, Montgomery, Ohio, assgnor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Appiication March 2,

5 Claims.

This invention relates to a switch for controlling an electrical circuit, and more particularly to a switch for that purpose having a temperature responsive control f thereon.

An object of this invention is to provide a switch that can be. manually operated to two positions, and automatically operated from one of said positions to the other of said positions ,in response to a temperature change.

Another object of this invention is to provide a manually operable switch for controlling an electrical circuit, said switch being provided with means for eiecting automatic control in response to the heating effect of the current in said'circuit.

Another object of this invention is to provide a rugged switch for controlling an electrical circuit and having few operating parts, which switch establishes and breaks the circuit with a snap action and has thermostatic latch means for controlling the switch in response to temperature.

In the drawing:

Fig. l is a plan view of the switch with the cover removed and showing the various elements of the switch in circuit closing position.

Fig. 2 is a view similar to Fig. 1 except that the switch elements are shown in circuit opening position.

Fig. 3 is a cross sectional view taken substantially along the line 3-3' of Fig. 1, showing the switch with the cover on.

Fig. 4 is a cross sectional view taken substantially along the line 4--4 of Fig. 1, also the switch with cover on.

Fig. 5 is a cross sectional view taken substantially along the line 5--5 of Fig. 1, and also showing the switch with the cover on.

Fig. 6 is a `fragmentary sectional view takenv a stud I2 which is secured to a bottoni wall i4 of the base i0, is an operating member I6. The member i6 has a. handle portion i8 extending through a recess in the base l0, formanual1y actuating the switch. Mounted on the member I6 on the opposite side of the pvot stud I2 from the lever portion I8, is a stud 22. A contact carrying member or bracket 24, preferably formed substantially as shown in Figs. 1 and 4, is pivotally supported on the stud 22. Attached to an extending arm portion 26 of the Contact carrying .showing i934, serial No. 713,633

member 24 by rivets 28 or other suitable fastening means, is a strip of insulating material 3E which carries a movable circuit closing member 32.

A stationary contacting member 40, having an extended portion 42 resiliently supporting an integral contacting portion L34 formed on its end, is mounted within a covering or reinforcing element 46 having dropped or flanged edges 48. n order to guide the contacting portion 44 and retain it in correct position, its free end is extended through a slot 50 in a dropped end portion 4l of the covering element 46. ".lhe other end of the covering element @6 and the corresponding end of the contacting member d0 are secured to the base i8 by means of a bolt 52 and cooperating nut 54 and washers 56 or other suitable fastening means. The bolt 52 and its cooperating nut 54 and washers 56 also serve as a binding post or terminal for a lead 58 of the circuit to be controlled by the switch which lead 58 is preferably provided with a lug 59 that is secured by the nut 54 between the washers 56. Another stationary contacting member 50, secured to the base i0 by bolt 52 and cooperating washer 64 and nut 66 or other suitable means, has a resilient portion 68 which supports contacting portion 'i0 that is preferably integrally formed with the portion 68. As shown in Fig. 5, the contacting portions 44 and 10 of the stationary contacting members 40 and 60 respectively, are in opposed spaced relation to each other and normally biased so that when the movable contacting member 32 is moved between them to close the circuit, it is yieldingly engaged between the members 40 and 60 so that good contact is made therewith.

A heating element 80 mounted within the casing i0, as shown in Figs. l and 2, has one end electrically connected to the stationary contacting member 60 by the bolt 62 and a cooperating retaining washer 8|. The other end of the heating element 80 is supported by a bolt 82 and a cooperating retaining washer 83. The bolt 82 which has a cooperating nut 84 and washers 86 also serves as a binding post or terminal for electrically connecting the heating element 80 with a lead such as 88 of the circuit to be controlled bythe switch which lead is preferably provided with a connecting lug 89.

Mounted between opposite walls of the casing il! and adjacent the heating element 80, so as to be in heat receiving relation therewith, as shown in Figs. 1 and 2, is abime'tallic strip or thermostatic element 90. The thermostatic element 90 has a catch 92, preferably struck therefrom, and designedto engage a latch portion 99 that is preferably formed on an extending arm 96 of the carrying member 29. When the switch is in the circuit closing position as shown in Fig. 1, the latch portion 94 is urged against the catch 92 by a spring or resilient member 98 which has one end secured to an vextending arm |90 that is preferably formed on the carrying member 29. The other end of the spring 98 is anchored to a post |02 within the base Ill. The switch is thus held in circuit closing position against the tension ofv the spring 98.

When the switch is connected in a circuit to be controlled, the current will flow through the bolt 52, stationary contact 40, circuit closing element 32, stationary contact G9, heating element 80, and bolt 82. With the heating element 89 so connected, it is obvious that any abnormal or excessive current flow thru the heating ele,

ment will cause it to heat the bimetallic strip 90 and ex the bimetallic strip as shown in Fig. 2. Such iiexing or warping of the bimetallic strip 9i) will eiect disengagement of the catch 92 and the latch 94 to allow the entire movable switch assembly to be moved by the spring 98 about the pivot stud I2 in a counter-clockwise direction as viewed in Figs. l and 2, and with a snap action, to the circuit open or oi position. A preferably integral arm and lug portion I5 of the operating member I6, which rests against a portion 25 of the Contact carrying member 2li between the stud 22 and the arm 26, and on the side of the portion 25 opposite the latch 99,v provides a one-way driving connection between the contact carrying member and the operating member I6. It is obvious that without the arm and lug portion l5 the contact carrying member 29 would pivot about the stud 22 instead of the pivot stud l2 and the manual operating lever i8 would not be shifted tothe oil position when the latch 99 is released by the catch 92.

To reset the switch to the circuit closing position, the actuating lever i8 is moved to the left, as viewed in Figs. 1 and 2, about the pivot stud l2 causing the lug l5 to urge the contact carrying member 29 to the right against the tension of the spring 99 until` the latch 99 engages the catch 92. It will be understood, oi course, that the latch 916 will not engage the catch 92 unless the bimetallic strip 99 is cool and in its normal position.

When it is desired to manually open the circuit, the actuating lever i8 is moved to the right as viewed in Fig. 2. This causes the stud 22, which pivotally supports the carrying member 2li, to be shifted to the left. By so shifting the contact carrying member, the latch 99 is disengaged from the catch 92 to permit the spring 98 to disengage the circuit closing element 32 from the stationary contacts i9 and 'Eil with a snap action.

The base i is shown as having a suitable cover H9 tted or otherwise securedto the base, and cooperating with the base l0 to enclose the switch mechanism. A traverse wall M2, as shown in Fig. 5 extends between the opposite walls of vthe cover H0, and adjacent the bimetallic strip 9@ to form a partial enclosure for the heating ele-v ment 89. By enclosing the heating element 89 in this manner, the heat emitted. by it is confined more closely to the bimetallic strip and will more readily aiect the bimetallic strip 99, thus increasing the eiciency of the switch.

While the present embodiment o f this invention, as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A thermal responsive switch comprising, in combination, cooperating contacts, a movable contact carrying member supporting one of said contacts and adapted to iect engagement and disengagement of said contacts, a movable pivotal support for said contact carrying member, an operat ng member foreiecting movement of the contact carrying member in one direction, a spring for effectinglmovement of the contact carrying member in the other direction, a latch portion on one of said members, and a thermostatic member for latchingly engaging said latch port'on to hold the contact carrying member in the position to which it lis operated by the operating member, said operating member eiectin'g movement of said' movable pivotal support to eiect manual disengagement of the latching portion from the thermostatic member. 1

2. A thermal responsive sw.tch comprising, in combination, cooperating contacts, 'a movable contact carrying member supporting one of said contacts and adapted to eiect engagement and disengagement of said contacts, a pivotally mounted` operating member for actuating the contact carrying member in one direction, a spring for eiecting movement of the contact carrying member in the other direction, a pivotal support for the contact carrying member secured to the operating member, and moved thereby, a latch portion on said contact carrying member, and a thermostatic member for latchingly engaging the latch portion to hold the contact carrying member in the position to which it is moved by the operating member, said operating member eecting movement of said movable pivotal supportv for manually .disengaging the latching portion from the thermostatic member.

3. A thermal responsive switch comprising, in

combination, cooperating contacts, a movable contact carrying member supporting one of said contacts and adapted to effect engagement and disengagement of said contacts, a pivotally mounted operating member for actuating the contact carrying member in one direction, a

- spring for eiecting movement of the contact carrying member in. the other direction, a pivotal tov tion on. said contact carrying member, and a. thermostatic member for latchingly engagingV the Ilatch portion to hold the contact carrying mem- HAROLD. E. COBB. 

